Medical eth­ics is the sci­ence of sur­vi­val. It stud­ies the work­ing out of judg­ments on ­right or ­wrong ­referred to the ­human ­being as a bio­log­i­cal ­entity inter­act­ing ­with the ­whole eco­sys­tem. Medical ethics in clinical research raises numerous moral and technical issues. Methodolog­i­cal ­aspects are essen­tial for car­ry­ing out the aim of clin­i­cal ­research. Medical eth­ics doc­u­ments are ­inspired by the Nuremberg ­Code and cul­mi­nate in the recent­ly updat­ed Helsinki Declaration of 1964. In Italy 2 min­i­ste­ri­al ­decrees in 1997 and 1998 ­laid the bas­is for the work of a med­i­cal eth­ics com­mit­tee. They acknowl­edge the European Good Clinical Practice Guidelines and set pro­fes­sion­al­ ­needs with­in eth­i­cal com­mit­tees. In clin­i­cal ­research the use of ion­is­ing radi­a­tion merits spe­cial con­sid­er­a­tion. In the ­recent ­past, seri­ous ­human ­rights abus­es in radi­a­tion experi­ments ­of the 1950s and 1960s ­have ­been ­found. As ­regards ­research in ­this ­field we can ­refer to the pub­li­ca­tion of the International Commission on Radio-logical Protection (­ICRP) and to the ­report of the World Health Organi-sation (WHO). Leg­is­la­tive ­decree no. 187 of May 26, 2000, which transposed the 97/43/ EURA­TOM Direc­tive rep­re­sents the ­most com­pre­hen­sive and ­recent nor­ma­tive ref­er­ence to clin­i­cal ­re-search ­using ion­is­ing radi­a­tion. However, law no. 39 of March 1, 2002 is impor­tant for the par­tial mod­ifi­ca­tions of pre­vi­ous ­decrees (art. 108 of L.D. no. 230 of March 17, 1995 and, art. 4 and ­attachment III of L.D. no. 187 of May 26). In ­this ­paper med­i­cal eth­ics, ­research, method­o­log­i­cal ­issues and ­aspects of ion­iz­ing radi­a­tion are dis­cussed.